Quaternary ammonium salts are broad-spectrum antimicrobial and antibacterial compounds commonly used in hard surface disinfectant products. They are typically available in commercial cleaning formulations with at least one surfactant and at least one organic solvent.
A particularly rigorous application of hard surface cleaning compositions is the class of hospital disinfectant products. Such products must be registered with the United States Environmental Protection Administration. Registration with the EPA requires submission of data establishing the disinfecting efficacy of the product. For example, DIS/TSS-1 Jan. 22, 1982 specifies the Efficacy Data Requirements for Disinfectants for Use on Hard Surfaces for hospital or medical environment claims. Label claims for use of disinfectants in hospital or medical environments are acceptable only for those products that are effective for general or broad-spectrum disinfection, particularly Staphylococcus aureus and Salmonella enterica, and additionally against the nosocomial bacterial pathogen Pseudomonas aeruginosa. In general, the test requirements for hospital disinfectant label usage require meeting the standards of the AOAC Germicidal Spray Products Test (Method No. 961.02), e.g., sixty carriers must be tested against each of Salmonella enterica ATCC 10708, Staphylococcus aureus ATCC 6538, and Pseudomonas aeruginosa ATCC 15442. For a product to be labeled as a disinfectant, it must kill 59 out of each set of 60 carriers, to provide effectiveness at the 95% confidence level. If the product is in the form of a towelette, the product will need to be tested in accordance with the test procedure specified in the American Society for Testing and Materials (ASTM) International's Standard Practice for Evaluation of Pre-saturated or Impregnated Towelettes for Hard Surface Disinfection (E2362-09), or the EPA's Standard Operation Procedure for Disinfecting Towelette Test against Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica (SOP # MB-09-04, Revised Feb. 26, 2010).
A supplemental standard is also established under DIS/TSS-6 for Efficacy Data Requirements for Supplemental Efficacy Claims specifically, for labeling a product with an efficacy claim with respect to Mycobacterium tuberculosis. Effectiveness against Mycobacterium tuberculosis is a highly important quality for products used in cleaning medical inhalation therapy and/or pulmonary diagnostic equipment. The test requirement for making a labeling claim of effectiveness against M. tuberculosis is substantiating data derived on 10 carriers by the AOAC Tuberculocidal Activity Method (II Confirmative In Vitro Test for Determining Tuberculocidal Activity) for each of two (2) samples representing two (2) different batches of a liquid product under test. If the product is in the form of a towelette, the product will need to be tested in accordance with the test procedure specified in the American Society for Testing and Materials (ASTM) International's Standard Practice for Evaluation of Pre-saturated or Impregnated Towelettes for Hard Surface Disinfection (E2362-09), or the EPA's Standard Operation Procedure for Disinfecting Towelette Test against Mycobacterium bovis (BCG) (SOP # MB-23-01, Revised Feb. 26, 2010). To make the label claim, the tested product must kill the test microorganism on all carriers, and no growth in any of the inoculated tubes of two additional media is permitted. If a product has not met this standard it may not be sold absent a label recommendation which clearly excludes the use of the product on inhalation therapy and/or pulmonary diagnostic equipment or a statement that the product has not been tested for such activity.
In addition to germicidal efficacy, hospital disinfectant products should have low toxicity, low odor, non-flammability, low skin irritation and no staining upon contact with a surface, leave a minimum of discernible residue, clean well, and be competitively priced.
U.S. Pat. No. 5,444,094 to Stepan Company discloses a tuberculocidal composition which comprises a quaternary ammonium salt, a glycol ether at a range of 8 w/w % to 80 w/w %, a strong alkali compound such as sodium metasilicate, and a chelating agent such as ethylenediaminetetraacetate (EDTA). While the composition is able to kill tuberculosis-causing bacteria, it requires a medium to high level of the glycol ether and a strong alkali compound to enhance the germicidal effect of the quaternary ammonium salt, and it has not been shown to have 100% efficacy in killing tuberculosis-causing bacteria.
Thus, there continues to be a need in the hospital disinfectant market for disinfectant quaternary ammonium salt products that are efficient at killing tuberculosis-causing bacteria and provide rapid disinfecting properties after its application to a surface.